Human NLRP11 function in non-canonical inflammasome activation by bacterial pathogen LPS

人类NLRP11在细菌病原体LPS非典型炎症小体激活中的作用

• 批准号: 10563477
• 负责人: Marcia B Goldberg
• 金额: $ 53.09万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-06 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10563477
• 关键词: Adaptor Signaling Protein; Bacteria; Binding; CASP1 gene; CASP4 gene; CASP5 gene; Caspase; Cell Death; Cell Death Induction; Cell surface; Cells; Communities; Complex; Cytosol; Data; Dependence; Dimerization; Family; Glycolipids; Goals; Human; Immune system; In Vitro; Infection; Infection Control; Inflammasome; Innate Immune System; Ligands; Lipopolysaccharides; Listeria monocytogenes; Macrophage; Mediating; Membrane; Micelles; Modification; Molecular; Mus; Mutation; Myelogenous; Pathogenesis; Pathway interactions; Pattern recognition receptor; Physiological; Positioning Attribute; Primates; Process; Proteins; Rest; Role; Shigella flexneri; Signal Transduction; Specificity; TLR4 gene; Testing; Transfection; Variant; cytosolic receptor; genome wide screen; insight; interest; member; microbial; molecular domain; mutant; pathogen; pathogenic bacteria; response; sensor

The gram-negative bacterial outer membrane glycolipid lipopolysaccharide (LPS) is recognized by both the cell surface TLR4 complex and cytosolic sensors. Recognition of bacterial LPS in the cytosol induces the activation of the caspase-4/caspase-5 (CASP4/5, human) or CASP11 (mouse) inflammasome, signaling platforms that trigger pyroptotic cell death. The dogma for recognition of bacterial LPS, based on the simplest interpretation of non-physiological data showing that CASP4/11 bind bacterial LPS in vitro, is that cytosolic bacterial LPS is directly sensed by CASP4/11 rather than by a pattern recognition receptor. We recently found that NLRP11, a poorly characterized primate-specific member of a family of pattern recognition receptors, is a pattern recognition receptor for cytosolic bacterial LPS. We found that efficient cell death induced by cytosolic bacterial LPS in human macrophages depends on NLRP11 function in the CASP4 inflammasome pathway. We initially identified NLRP11 in a genome-wide screen of human myeloid-derived cells for factors that promote cell death during infection with the gram- negative bacterial pathogen Shigella flexneri. We propose to leverage our findings to uncover mechanisms of NLRP11 function in cytosolic bacterial LPS-triggered activation of the human CASP4 inflammasome, including the role of variants of S. flexneri LPS in this process. 1. Define determinants of host-pathogen interaction of NLRP11 with bacterial LPS and caspase(s) and of NLRP11 specificity for caspase(s). We will define the molecular domains and sequences that mediate bacterial LPS interaction with NLRP11 and NLRP11 with CASP4. 2. Determine mechanisms of host NLRP11-mediated activation of CASP4 in response to cytosolic bacterial pathogens and cytosolic bacterial LPS. We will test our hypothesis that resting state NLRP11 is autoinhibited and activated NLRP11 triggers CASP4 activation by proximity-induced dimerization and will test the requirements for bacterial LPS in NLRP11 activation. 3. Test whether host NLRP11 recognition is modulated by specific LPS modifications or modes of LPS delivery by gram-negative bacterial pathogens. We will determine the role of selected modifications of LPS from S. flexneri on its recognition by NLRP11 and on NLRP11-dependent CASP4 activation and will test our hypothesis that NLRP11 is most critical to CASP4 responses when S. flexneri LPS is in micelle-reducing conditions. Our focus is to determine mechanisms of cytosolic bacterial LPS-triggered NLRP11-mediated activation of the human CASP4 inflammasome. We are uniquely positioned to accomplish these goals. Our insights are likely to have broad implications for gram-negative pathogenesis and thus be of great interest to the pathogenesis community.

革兰氏阴性细菌外膜糖脂脂多糖（LPS）被两者识别 细胞表面 TLR4 复合物和胞质传感器。识别细胞质中的细菌 LPS 会诱导 激活 caspase-4/caspase-5（CASP4/5，人）或 CASP11（小鼠）炎症小体，信号传导 触发焦亡细胞死亡的平台。基于最简单的细菌 LPS 识别法则 对显示 CASP4/11 在体外结合细菌 LPS 的非生理数据的解释是，胞质 细菌 LPS 直接被 CASP4/11 感知，而不是被模式识别受体感知。我们最近发现 NLRP11 是一个模式识别受体家族的灵长类特异性成员，其特征尚不明确，是一个 细胞质细菌 LPS 的模式识别受体。 我们发现，人巨噬细胞中胞质细菌 LPS 诱导的有效细胞死亡取决于 NLRP11 在 CASP4 炎症小体途径中发挥作用。我们最初在全基因组范围内鉴定了 NLRP11 筛选人骨髓源性细胞，寻找在革兰氏阴性菌感染期间促进细胞死亡的因素 阴性细菌病原体福氏志贺氏菌。我们建议利用我们的发现来揭示机制 NLRP11 在胞质细菌 LPS 触发的人 CASP4 炎性体激活中发挥作用，包括 福氏链霉菌 LPS 变体在此过程中的作用。 1. 定义 NLRP11 与细菌 LPS 和 caspase 的宿主-病原体相互作用的决定因素 以及 NLRP11 对 caspase 的特异性。我们将定义分子结构域和序列 介导细菌 LPS 与 NLRP11 以及 NLRP11 与 CASP4 的相互作用。 2. 确定宿主 NLRP11 介导的 CASP4 响应胞质的激活机制 细菌病原体和细胞质细菌脂多糖。我们将检验我们的假设，即静息态 NLRP11 是 自动抑制和激活的 NLRP11 通过邻近诱导二聚化触发 CASP4 激活，并将测试 NLRP11 激活对细菌 LPS 的要求。 3. 测试宿主NLRP11识别是否受到特定LPS修饰或LPS模式的调节 革兰氏阴性细菌病原体传递 LPS。我们将确定所选修改的作用 来自福氏链霉的 LPS 被 NLRP11 识别以及 NLRP11 依赖性 CASP4 激活，并将进行测试 我们的假设是，当福氏链霉 LPS 处于胶束还原状态时，NLRP11 对 CASP4 反应最为关键 状况。 我们的重点是确定细胞质细菌 LPS 触发的 NLRP11 介导的激活机制 人类 CASP4 炎症小体。我们处于实现这些目标的独特位置。我们的见解是 可能对革兰氏阴性菌的发病机制具有广泛的影响，因此引起了人们的极大兴趣 发病机制群落。